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Proteomics
About Proteomics Proteomics is the study of proteins and the structure, functionality, interaction between other proteins, and how they function in our bodies.This project (and many others) were created after the Human Genome Project (HGP). The Human Genome Project was completed in April 2003. The main goal of the HGP was to sequence a whole human genome. But what do we do with this information? With the genetic sequence we can learn more about the different kinds of proteins that our bodies produce. Our genes encode for these proteins, but we have limited knowledge about how they function in our bodies. With proteomics, scientists are exploring post translational modifications that are made to our proteins and much more. This is just the beginning of understanding how complex and cool the human body really is. Methods in Proteomics There are many different methods that are used in the field of proteomics. These two methods are not the end all be all, but they are the most commonly used in this field of study. Mass Spectrometry (MS) This is an analytical chemistry technique that helps scientists identify the amount and type of chemicals present in a sample. The sample goes four simple steps - Ionization, acceleration, deflection, and then detection and analysis. The first step is that the sample must be ionized and accelerated. This can be done in many different ways. A sample can be accelerated through a small hole and be sprayed out (ion spray) or the sample can be placed on a surface and a laser can be shot at it which ionizes it. After the sample becomes ionized, it is accelerated through a cylinder and is deflected by an electromagnetic field, The range of deflection depends on how fast the sample is traveling, what the chemicals are, and how dense they are. The last step is the ion detection by a computer. This produces a mass spec graph that shows the mass to charge ratio and the abundance of ions in the sample. This method is used in proteomics because it can label certain parts of a protein and then the scientists can see what peptides are in the protein as well as help resolve what proteins are present in a large sample. Protein Detection with Immunoassays (i.e. ELISA) ELISA or Enzyme-Linked ImmunoSorbent Assay is a biochemical test that uses antibodies to produce a color change based on the identity of the sample. How it works is very simple. First a ninety-two well plate is coated with antibodies in each well that are specific to the protein that you want to find in your samples. One washes the protein sample over the wells and then the protein will attach to the antibodies in the wells. Then two additional washes of other antibodies are added for the visualization to occur. Then in the final wash, a chemical is washed over the wells and then a color change occurs. If a color change occurs, this means that the protein of interest in that particular well. This is used in proteomics to help identify different proteins in samples. This can be better that MS because it is antibody specific. Limitations of Proteomics Proteomics is not the answer to all our questions about the human body. The major draw back to these experiments is that they are not able to replicated easily. This is due to the fact that many post translational modifications are made to proteins that we have not been able to see. For example, a protein may not be turned "on" until it is phosphorylated. So until that event occurs, that protein will be dormant. Another problem is protein degradation. If a protein is not used, it is degraded so that the body can use its peptides for other proteins that need to be formed. This is true for m-RNA's since they are so small. If they are not used, they are degraded. References "The Human Genome Project", National Human Genome Research Institute, National Institutes of Health, March 18, 2014. Retrieved: November 29 2014. "Proteomics", Wikipedia, Retrieved: November 29, 2014. "Mass Spectrometry", Wikipedia, Retrieved: November 29, 2014. "Bioinformatics approaches for the functional interpretation of protein lists: from ontology term enrichment to network analysis", Laukens K. et. al, Proteomics. 2014 Nov 28. doi: 10.1002/pmic.201400296. PMID: 25430566.